The present invention relates to a sputtering device, and more particularly, to a sputtering device which improves the adhesion of film to be deposited by introducing a pair of gratings to a shield.
A sputtering device makes high energy particles collide with a predetermined substance, e.g., the surface of a target. As a result, atoms of the target are ejected whereby a film is grown on a substrate. The sputtering device is widely used for depositing various metal films on the substrate during VLSI manufacturing processes. Also, the sputtering device can be used for forming an insulating layer or a refractory metal layer, which is formed by a general chemical vapor deposition method.
FIG.1 is a diagram schematically showing an apparatus for sputtering according to a conventional art.
First, the major constituent elements of the device will be explained via reference numerals. Reference numerals 1, 2, 4, and 6 represent the chamber of the sputtering device, a first electrode (anode) which supports the substrate (wafer) and is used as an electrode, a silicon substrate on which a film is to be formed, and a revolving shaft for revolving a chuck used as the first electrode, respectively. Also, reference numerals 8, 10, 12, and 20 represent a target composed of a source material to be sputtered, a second electrode (cathode) attached to the target, a shield portion located below the target, and a power supply, respectively.
Next, a process of forming a film on the substrate (wafer) using the conventional sputtering device will be explained.
An inert gas, e.g., argon, is injected into the vacuum chamber 1 having high-voltage electrodes 2 and 10, whereby the argon gas is formed into a plasma state 14, that contains argon ions (Ar+) 16. These plasma ions 16 are accelerated onto target 8 mounted on an oppositely charged electrode 10, that is, negatively charged, by an electric field and collide with target 8. By colliding with target 8, the plasma ions 16 eject the source material from target 8. Also, plasma ions 16 are neutralized and continuously move toward the lower positioned substrate 4. The ejected particles of source material move toward the semiconductor substrate 4, thereby forming a film having a predetermined thickness o substrate 4.
Especially, particles moving near shield portion 12 during sputtering, e.g., sputtered particles or neutralized plasma ions 16, move toward the lower positioned substrate 4 according to a path 15 having a slight angle. When the particles (shown by arrow 18) moving at the slight angle become spread out near the edge portion of the substrate, a tensile stress is generated in the thus-coated film, thereby decreasing adhesion.